1. Field of the Invention
The present invention relates to a digital communication path network, and more particularly, to a digital communication path network having time division switches and a cell switch as a space division switch in which the 64-Kbps (bits/s) base service and the broadband switching service can be provided to perform a multiple connection of communication paths for broadcasting.
2. Description of the Related Art
A space division switch, comprised of a conventional digital communication path network of a digital switching system, performs a function that a time slot data multiplexed to 64 Kbits/s and having been inputted in a certain input highway is to be outputted into the same time slot location of a specified output highway. When a higher transmission speed more than 64 Kbits/s is required in the digital switching system, e.g., 64.times.n bits/s and H0/H1 service using the H channel, a plural number of time slots are used for switching such a high speed data.
A conventional digital communication path network including a space switch can also perform a multiple connection which outputs the same data having been inputted from a specified input port to a plural number of output ports. The Japanese Patent Laid-open No. 57-143967 or No. 60-140969 discloses this multiple connection technology of a digital communication path network. An example of the digital communication path network used in a conventional digital switching system is shown in FIG. 1. The digital switching system includes a main controller 200. In a case where an audio signal or data as user information from a telephone 201 is to be transmitted to a telephone 220, the telephone 201 generates communication path connection information which is supplied to the main controller 200 via a subscriber circuit 202 and the main controller 200 controls controllers 206a, 210a and 212a based on the communication path connection information. Also, the telephone 201 outputs the audio signal or data as the user information to a concentration switch 204 via the subscriber circuit 202. The concentration switch 204 selects the audio signal or data supplied from the telephone 201 as a transmission signal to output to a primary time division switch 206. The primary time division switch 206 performs time division multiplexing (TDM) for the transmission signal and a time slot switching under control of the controller 206a to produce a TDM signal and output it to a space division switch 210. The space division switch 210 outputs the TDM signal to a specified secondary time division switch 212 under control by the controller 210a. Under control by the controller 212a, the secondary time division switch 212 performs a time slot switching and supplies the TDM signal as the transmission signal to the telephone 220 via a concentration switch 216 and a subscriber circuit 218. The same matter is performed in a case of using time division switches 208 and 214, controllers 208a and 214a, a concentration switch 222, a subscriber circuit 224 and a telephone 226. In this manner, the user information from the telephone 201 can be transmitted to the telephone 220.
When a multiple connection of communication paths is required for broadcasting an audible signal and/or announcement messages to unspecified number of subscribers, such a signal resource is to be connected through the space division switch to the input port of all secondary time division switches by which the multiple connection is performed.
On the other hand, there is the demand for broadband switching service for higher speed transmission. In the broadband switching service, the cell base switching service is required as represented by an asynchronous transfer mode (ATM). Therefore, a cell switch network is necessary.
Therefore, a digital communication path network having time division switches and a cell switch as a space division switch should perform the complicated connection control for signal broadcasting in which a signal resource is to be connected to the input port of the cell switch and to be distributed to the secondary time division switches through the cell switch.